Effect of secondary vanadium carbide (VC) addition on the mechanical properties and wear mechanism of TiC–Ni cermets fabricated by spark plasma sintering

This study investigates the effect of secondary vanadium carbide (VC) on the mechanical properties and wear behaviour of TiC-Ni cermets. The cermets were fabricated from TiC, Ni, and 1, 3, and 5 vol% VC, while the nickel content was fixed at 5 vol%. Spark plasma sintering (SPS) was carried out at 1280 °C under an applied pressure of 50 MPa for 8 min. The relative density of the VC-free sample reached 97.41% and increased to above 98% with VC addition. Phase analysis indicated a significant reduction in free nickel with increasing VC content. Microstructural observations revealed the formation of a grey interfacial region in SEM images, accompanied by a decrease in free Ni and isolated TiC grains. Hardness increased from 15.34 GPa for the VC-free cermet to 16.71 GPa for the sample containing 5 vol% VC. Fracture toughness showed a moderate increase from 7.20 MPa·√m to 7.61 MPa·√m with VC addition. Wear tests demonstrated a pronounced reduction in wear rate, decreasing from 8.6 × 10 − 3 mg·m − 1 for the VC-free sample to 4.2 × 10 − 3 mg·m − 1 for the cermet containing 5 vol% VC. These results suggest that secondary VC addition improves densification and microstructural characteristics, resulting in enhanced mechanical performance and wear resistance.